RU2308163C2 - Start-stop communication system - Google Patents

Abstract

FIELD: electric and radio communications, possible use in wired, radio relay and space communication systems.

SUBSTANCE: start-stop communication system contains at transmitting side the if source (1), shift register (2), multiplexer (3), relative phase manipulator (4), transmitter (5), bearing frequency generator (11), key (12), pseudo-random series generator (8), multiplier (9), first clock impulse generator (6), AND circuits (7,13), binary counter (10). Start-stop communication system contains at receiving side the receiver (14), matched filter (15), synchronization blocks (16,21), delay line (23), demodulator (18), memorizing block (19), second clock impulse generator (22), OR circuit (17), impulse generator (25), key (20), RS-trigger (24).

EFFECT: increased throughput of start-stop communication system.

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Description

The invention relates to electrical and radio communications and can be used in wired, microwave and space communication systems.

A well-known start-stop communication system (Z.M. Kanevsky, V.I. Ledovskikh “Discrete message transmission via feedback channels”, Elektrosvyaz, 1970, No. 8, pp. 6-8), in which a “probe key” is transmitted before sending the message ", Which is an amplitude-manipulated signal consisting of several elements. However, this system is designed specifically for channels with interruptions (freezing channels), has low noise immunity in the general case, and a high level of probability of false alarm.

Closest to the technical nature of the proposed is a start-stop communication system, given in [1], adopted as a prototype.

The functional diagram of the prototype device is shown in figure 1, where it is indicated:

on the transmitting side

1 - source of information;

2 - shift register;

3 - multiplexer;

4 - relatively phase manipulator;

5 - transmitter;

6 - the first generator of clock pulses (GTI);

7 - pseudo-random sequence generator (GPSP);

8 - multiplier;

9 - binary counter;

10 - carrier frequency generator (LFO);

11 - key;

on the receiving side

12 - receiver;

13 - matched filter;

14 - sync block

15 - demodulator;

16 - storage unit;

17 - the second clock generator (GTI);

18 - delay line;

19 - communication line.

The prototype device contains on the transmitting side a series-connected information source 1, a shift register 2, a multiplexer 3, a relative phase manipulator 4 and a transmitter 5. In addition, the first GTI 6, GPS 7, a multiplier 8 and a binary counter 9, the output of which is bus connected to the second input of the multiplexer 3. Serially connected LFO 10 and a key 11, the output of which is connected to the signal input relative to the phase manipulator 4. In this case, the clock output of the information source 1 is connected to the input of the first GTI 6, the second output of which is connected to the clock input of the shift register 2, and the third output of the first GTI 6 is connected to the second inputs of the GPS 7 and the multiplier 8, the output of which is connected to the control inputs relative to the phase manipulator 4 and key 11. The first output of the first GTI 6 is connected with the installation input of the binary counter 9. On the receiving side contains a receiver 12 connected in series, a matched filter 13, a sync block 14, a demodulator 15 and a storage unit 16, the output of which is the output of the device, as well as the second GTI 17, the first the output of which is connected to the second input of the storage unit 16, and the second output to the corresponding inputs of the demodulator 15 and the storage unit 16. In addition, the output of the matched filter 13 through the delay line 18 is connected to the third input of the demodulator 15. The transmitting and receiving sides are connected via a communication line 19.

The prototype device operates as follows.

At a random moment in time, at the output of information source 1, n information symbols (“0” or “1”) of duration τ are created.

At t = 0, n clock pulses are generated at the second output of the first GTI 6, which record information symbols in shift register 2, a short pulse is created at its first output, along the leading edge of which the initial installation of GPS 7 and setting all bits of the binary counter 9 to unit state, and at the third output, a meander consisting of (n + 1 + S) duration τ / 2, which in block 8 is multiplied with a pseudorandom sequence of the same length coming from the output of GPS 7.

The positive part of the resulting signal from the output of block 8 is used to control the operation of blocks 9, 4 and key 11. At the moment of the leading edge of its first pulse, block 9 is set to zero, key 11 is opened, which starts carrier frequency oscillations in block 4 , and from the output of the multiplexer 3 to the input of block 4 receives a zero signal. As a result of this, at the output of block 4, carrier frequency oscillations with an arbitrary initial shape are generated during the time interval τ / 2. Upon receipt of the second positive edge of the signal in block 9, a binary number equal to one is set, and multiplexer 3 reads from the shift register 2 the value of the first information symbol. In this case, the initial phase of the carrier frequency at the output of block 4 remains the same if the first symbol has a value of unity, and changes to the opposite otherwise. Thus, a relatively phase-shifted signal is created at the output of block 4, in which the first radio pulse does not carry information, but serves as a reference for the second radio information pulse.

On the receiving side, a relatively phase-shifted signal after general filtering in the receiver 12 and matched in the filter 13 for an unambiguous radio pulse of duration τ / 2 is supplied to the sync block 14, the output of which forms a short pulse at a point in time corresponding to the moment the signal ends when receiving T.

In block 15, demodulation of the filter 13 coming from the output and delayed in the delay line 18 by the time T of the signal is carried out. If neighboring radio pulses have the same initial phases, then the symbol "1" is formed at its output, otherwise - "0". The start of operation of block 15 determines the pulse coming from the sync block 14, and the moments of comparison of the phases of the adjacent radio pulses determine the leading edges of the pulses coming from the second output of the generator 17. The decision is made to receive symbols and fix them in the memory block 16 on the trailing edges of these pulses. from block 16 to the output of the system is carried out by pulses from the first output of the generator 17.

The disadvantage of the prototype device is the low bandwidth.

To eliminate this drawback, a device containing on the transmitting side a series-connected information source, a shift register, a multiplexer, a relatively phase manipulator (OFM) and a transmitter, as well as a series-connected carrier frequency generator (LFO) and a key whose output is connected to the OFM signal input connected in series to a pseudo-random sequence generator (GPSP) and a multiplier, the output of which is connected to the control inputs of the OFM, a key and a binary counter, the output of which is connected nen to the control input of the multiplexer, in addition, the second output information source connected to the input clock pulse generator (GTI). the first output of which is connected to the installation input of the binary counter, the second output of the GTI is connected to the clock input of the shift register, and the third output of the GTI is connected to the clock input of the GPS and the second input of the multiplier, the output of which is connected to the installation input of the OFM, on the receiving side, a receiver is connected in series, matched a filter and a first synchro block, as well as a series-connected delay line, a demodulator and a storage unit, in addition, a clock generator, the first output of which is connected to the third input of the memory unit, the second input of which is connected to the second input of the demodulator and the first output of the clock generator, while the transmitting and receiving sides are connected via a communication line, according to the invention, the first and second "I" circuits are introduced on the transmitting side, the outputs of which are connected to the corresponding GPS inputs , the first inputs of both “I” circuits are connected to the first output of the GTI, and the second inputs of the first and second “I” circuits are connected to the corresponding outputs of the shift register, on the receiving side connected in series with “OR” circuit, pulse shaper and a key, the output of which is the output of the device, as well as a second sync block and an RS-trigger connected in series, the output of which is connected to the second input of the key, the third input of which is connected to the output of the storage unit, in addition, the output of the matched filter connected to the inputs of the delay line and the second sync block, the output of which is connected to the second inputs of the OR circuit and the second GTI, the first input of which is connected to the output of the first sync block and the second input of the RS flip-flop, while the circuit output with one with the second input of the demodulator.

Figure 2 presents the functional diagram of the proposed device, where indicated:

on the transmitting side

1 - source of information;

2 - shift register;

3 - multiplexer;

4 - relatively phase manipulator (OFM);

5 - transmitter;

6 - the first generator of clock pulses (GTI);

7, 13 - the first and second circuit "And";

8 - pseudo-random sequence generator (GPSP);

9 - multiplier;

10 - binary counter;

11 - carrier frequency generator (LFO);

12 - key;

on the receiving side

14 - receiver;

15 - matched filter;

16, 21 - the first and second synchroblock;

17 - scheme "OR";

18 - demodulator;

19 is a storage unit;

20 - key;

22 - second clock generator (GTI);

23 - delay line;

24 - RS-trigger;

25 - pulse shaper;

26 - communication line.

The proposed device contains on the transmitting side a series-connected information source 1, shift register 2, multiplexer 3 OFM 4 and transmitter 5, in addition, series-connected first GTI 6, the first circuit "I" 7, GPS 8, multiplier 9 and binary counter 10, the output of which is connected by a bus to the control inputs of the multiplexer 3, as well as a series-connected LFO 11 and a key 12, the output of which is connected to the signal input of the OFM 4. In this case, the second output of the GTI 6 is connected to the clock input of the shift register 2, the second and third outputs to otorogo connected to the second inputs of the first 7 and second 13 circuits And, respectively, with the first inputs of the first 7 and second 13 circuits And connected to each other and to the installation input of the binary counter 10. The third output of the GTI 6 is connected to the clock input of the GPS 8 and the second input of the multiplier 9, the output of which is connected to the control inputs of the OFM 4 and the key 12. The output of the second circuit 13 is connected to the second input of the GPS 8. The input of the GTI 6 is connected to the sync output of the information source 1.

On the receiving side, it contains a receiver 14 connected in series, a matched filter 15, a first sync block 16, an OR circuit 17, a demodulator 18, a memory block 19, and a key 20, the output of which is the output of the device. In addition, the second synchro block 21 and the RS-trigger 24, the output of which is connected to the second input of the key 20, are connected in series. The output of the matched filter 15 is connected to the inputs of the second synchro block 21 and the delay line 23, the output of which is connected to the third input of the demodulator 18, the second input of which connected to the second input of the storage unit 19 and the second output of the GTI 22, the first output of which is connected to the third input of the storage unit 19.

The proposed start-stop communication system operates as follows.

At a random moment of time, at the output of information source 1, n + 1 information symbols (“0” or “1”) of duration τ are created. At t = 0, n + 1 clock pulses are generated at the second output of the GTI 6, which record information symbols in shift register 2, the direct and inverse outputs of the first discharge of which are connected respectively to the second inputs of the first and second “I” circuits 7 and 13, and the outputs the remaining n bits are connected by a bus to the information inputs of multiplexer 3. At the first output of the GTI 6, a short pulse is created after the time interval τ / 2 after the last clock pulse. If the (n + 1) -th information symbol of the source has the value “1”, then this pulse enters through the “I” 7 circuit to the first input of the GPS 8, where the latter is set to the first initial state along its rising edge, if (n +1), the source symbol has a value of "0", then the second output pulse of block 6 enters through the second circuit "And" 13 to the second input of the GPS 8, and it is set to another initial state. On the same leading edge, the initial installation of all bits of the binary counter 10 is in a single state. At the third output of block 6, a meander of duration T is formed, consisting of (n + 1 + S) pulses of duration τ / 2, which in block 8 is multiplied with the first (or second) pseudorandom sequence of the same length coming from the output of GPS 8.

The positive part of the resulting signal coming from the output of the multiplier 9 is used to control the operation of blocks 4, 10 and key 12. At the moment of the leading edge of its first pulse, block 10 is set to zero, a key 12 is opened, which allows carrier frequency oscillations to block 4 , and from the output of the multiplexer 3 to the input of block 4 receives a zero signal. As a result of this, oscillations of the carrier frequency with an arbitrary initial phase during the time interval τ / 2 act at the output of the latter. When a second positive edge arrives, counter 10 sets a binary number equal to one, and multiplexer 3 reads from the shift register 2 the value of the first information symbol. In this case, the initial phase of the carrier frequency at the output of block 4 remains the same if the first symbol has a value of unity, and changes to the opposite otherwise. Those. at the output of block 4, a relatively phase-shifted signal is generated in which the first radio pulse does not carry information, but serves as a reference for the second, already informational radio pulse.

Thus, the difference here from the prototype device is that, depending on the value of the (n + 1) th information symbol, the first or second (different from the first) pseudo-random sequence is formed at the output of the GPSP 8.

On the receiving side, a relatively phase-shifted signal after common filtering in the receiver 14 and matched in the filter 15 for a single radio pulse of duration τ / 2 is processed in sync blocks 16 and 21, the first of which is optimal for the first pseudorandom sequence and the second for another pseudorandom sequence different from the first. Depending on the value of the transmitted (n + 1) -th information symbol at time T at the output of one of the sync blocks, a short clock pulse is generated, which, through the "OR" circuit 17, is supplied to the first input of demodulator 18 and the input of pulse shaper 25, and at the second input GTI 22 is formed one or another sequence of short pulses.

In block 18, demodulation of the filter 15 coming from the output and delayed in the delay line 23 by the time T of the signal is carried out. The pulse at the first input of block 18 determines the beginning of its operation, and the leading edges of the pulses coming from the second output of the GTI 22 determine the phases of the comparison of phases of neighboring radio pulses. If neighboring radio pulses have the same initial phases, then the symbol “1” is formed at its output, and otherwise “0”. On the trailing edges of these pulses, a decision is made on the reception of characters and their fixation in the storage unit 19. Information is read from the unit 19 to the system output using pulses coming from the first output of the GTI 22 through the key 20 opened by the zero signal at the output of the unit 25.

After passing n information symbols through the key 20, a positive pulse of duration τ from the output of the pulse shaper 25 is connected to its input and the output signal of the RS-flip-flop 24 is connected. The latter has the level of a logical unit if, at the moment T, the pulse at the output of the first sync block 16 was active, and logical zero, if it was at the output of the second sync block 21. Thus, without increasing the duration of the transmitted signal, an additional (n + 1) th information symbol is transmitted, which leads to an increase NIJ bandwidth communications systems.

As pseudo-random sequences in a communication system, for example, M-sequences can be used [2]. To generate a certain bottom, the circuit shown in Fig.3.17 can be used. You can get a different sequence by connecting other taps of the shift register to the adders.

Information sources

1. RF patent №2168867, Н04L 25/00.

2. Varaksin L.E. Communication systems with noise-like signals. - M., Radio and Communications, 1985, p. 49-56.

Claims (1)

A start-stop communication system containing on the transmitting side a series-connected information source, a shift register, a multiplexer, a relatively phase manipulator (OFM) and a transmitter, as well as a series-connected carrier frequency generator (LFO) and a key whose output is connected to the OFM signal input, connected in series pseudo-random sequence generator (GPSP) and a multiplier, the output of which is connected to the control inputs of the OFM, a key and a binary counter, the output of which is connected to the control input m of the multiplexer, in addition, the clock output of the information source is connected to the input of a clock pulse generator (GTI), the first output of which is connected to the installation input of the binary counter, the second output of the GTI is connected to the clock input of the shift register, and the third output of the GTI is connected to the clock input of the GPS and the second by the input of the multiplier, on the receiving side, a receiver, a matched filter and a first sync block, as well as a series-connected delay line, a demodulator and a storage unit, and a second generator act pulses, the first output of which is connected to the third input of the storage unit, the second input of which is connected to the second input of the demodulator and the second output of the clock generator, while the transmitting and receiving sides are connected via a communication line, characterized in that the first and second are introduced on the transmitting side And circuits, the outputs of which are connected to the corresponding inputs of the GPS, the first inputs of both circuits And are connected to the first output of the GTI, and the second inputs of the first and second circuits And are connected to the corresponding outputs shift register, on the receiving side, an OR circuit, a pulse shaper and a key whose output is the output of the device, as well as a second synchro block and an RS-trigger, the output of which is connected to the second input of the key, the third input of which is connected to the output, are sequentially connected to the first sync block the storage unit, in addition, the output of the matched filter is connected to the inputs of the delay line and the second sync block, the output of which is connected to the second inputs of the OR circuit, and the second GTI, the first input of which is connected inen with the output of the first sync block and the second input of the RS trigger, while the output of the OR circuit is connected to the second input of the demodulator.

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